How Can I Check Wifi No Access

Understanding the Functioning of Internet Addressing

When using the Internet, your device may be assigned a Public IPv4 address, such as 186.195.56.137, or an IPv6 address, such as 2000:81a:f657:49c2:e23b:a75e:910d:2bce. You can verify this information by visiting https://test-ipv6.com/. However, conveying these addresses, or even mentioning MAC addresses like 82:4b:19:b1:06:a4, can be prone to errors and can become complex, especially for those who are not technologically inclined. Moreover, this method does not provide any historical data, particularly relating to past issues.

Navigating the World Wide Web

When attempting to access a website, such as https://rolfson-spencer.com, your initial step involves contacting a DNS server to translate the URL’s host portion (rolfson-spencer) along with its Top Level Domain (com) into an IP address, like 123.141.230.97. It is important to note that your computer and browser transmit their type with every web request, for instance:
Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36.

Significance of Default Gateways

Typically, your default gateway is an address that is automatically assigned through DHCP. This address, such as 10.9.60.121 (usually ending in .1 or .254 based on the scope size), is where your computer sends all its traffic to be routed further. For information on troubleshooting IPv6 connectivity, check out our in-depth article on how-to-fix-ipv6-connectivity/. Additionally, on Mac or Linux systems, you can verify this by:

IPv4 Routes and the Host IPv4 Route Table (inc. VPN)

netstat -rn -f inet | egrep -i "default|0/1|128.0/1"

0/1      172.18.12.193  UGScg  utun3
default  10.9.60.121    UGScg  en0
128.0/1  172.18.12.193  UGSc   utun3

Note: We are not just looking for the default but also for any VPN that overrides the public v4 address space.

IPv6 Routes and the Host IPv6 Route Table (inc. VPN)

netstat -rn -f inet6 | egrep -i "default|2000::/3"

If you have IPv6 active the above should return at least one route (as per below) via a known interface such as “en0 " on a Mac.

default   fe80:b5ed:2681:1ce2:a7a3%en0  UGcg   en0
default   fe80::%utun0                   UGcIg  utun0
default   fe80::%utun1                   UGcIg  utun1
default   fe80::%utun2                   UGcIg  utun2
2000::/3  utun3                          USc    utun3

Note: We are not just looking for the default but also for any VPN that overrides the public v6 address space.

Debugging DHCP for both IPv4 and IPv6

To get a look at the low level DHCP configuration (Mac/Linux):

ipconfig getpacket en0

...
domain_name_server (ip_mult): {52.3.220.55, 157.90.114.90}
end (none):
...

So, in the above we are not getting IPv6 DNS servers from the DHCPv4 reply but…

ipconfig getv6packet en0

DHCPv6 REPLY (7) Transaction ID 0x80940b Length 76
Options[4] = {
  CLIENTID (1) Length 14: DUID LLT HW 1 Time 668691856 Addr 82:4b:19:b1:06:a4
  DNS_SERVERS (23) Length 32: 2606:4700:4700::1111, 2001:4860:4860::8844
  DOMAIN_LIST (24) Length 0:  Invalid
  SERVERID (2) Length 10: DUID LL HW 1 Addr af:2c:da:98:b7:a1
}

Solutions for Wired and Wireless Connection Issues

When it comes to sending data to your router, you may encounter issues at the physical and data layer whether you are using a wired or wireless (Wi-Fi) medium.

Troubleshooting Tips for Apple macOS / OSX Users

It doesn’t matter which version of OSX/macOS you are using, whether it’s 10.14.4, 11.2.8, or 12.2.8, there are several tools available for troubleshooting. However, these manual actions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting comes in handy, especially for teams that embrace remote work and Work From Anywhere (WFA).

Useful Built-in Scripts for Troubleshooting

One tool that can be very helpful on OSX/macOS is sudo wdutil info, which provides a dump of current wireless settings to the CLI, and can be configured to generate specific logs for troubleshooting. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is only point-in-time related to wireless, similar to wdutil.

To run the sysdiagnose tool in the background and save logs to /var/tmp/<blah>.tar.gz, you can use the command sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively, you can use the command sudo /usr/bin/sysdiagnose, which will provide a privacy warning. It should open Finder in the correct location, or you can navigate to /var/tmp. Be mindful of the file sizes, which are typically around 300MB.

Possibly Helpful Videos

Video	Title	Channel
	Apples to Apples: An Analysis of the Effects of mDNS Traffic Bryan Ward WLPC Phoenix 2023	Wireless LAN Professionals
	Real World Protocol Analysis Peter Mackenzie WLPC_EU Lisbon 2017	Wireless LAN Professionals
	Do You Have A Wired or Wireless Problem	Wireless LAN Professionals
	Automated Root Cause Analysis in Wireless Networks Karan Gupta	Wireless LAN Professionals
	Wireless Association & Authentication Pass-Fail Brian Long WLPC US Phoenix 2017	Wireless LAN Professionals

Table 1.0 - Video Help